Removal of tobacco smoke from air



June 5, 1934. w. K. GILKEY 1,961,378

REMOVAL OF TOBACCO SMOKE FROM AIR Filed Feb. 10. 1952 Far/f/ea 20 A I 19 1 fa/a/ys a Fade 1/00 12 6/10/21 her 16 Fan sformer 18 i 0 [/0 are Patented June 5, 1934 warren STATES REMOVAL OF TOBACCO SMOKE FROM AIR William K. Gilkey, Dayton, Ohio, assignor to Frigidaire Corporation, Dayton, Ohio, a corpo ration of Delaware Application February 10, 1932, Serial No. 592,201

4 Claims. (01. 23-4) This invention relates to chemistry and more particularly to the purification of air containing tobacco smoke and the like.

In places where large numbers of people congregate and smoke tobacco it has been a difficult problem to provide proper atmospheric conditions Without the necessity of introducing an excessive amount of fresh air. It is an object of this invention to provide a method or mechanism capable of purifying the air laden with tobacco smoke in such places in a manner that an undue introduction of fresh air is not necessary.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 shows diagrammatically a complete apt paratus embodying this invention; and

Fig. 2 shows diagrammatically a connection between the ozonizer and the transformer.

In practicing this invention preferably the air is circulated through a treating device, the air being withdrawn from and discharged to the space to be purified. The air passing through this device is subjected to the action of an ozonizer, thereafter passes through a, small reaction chamber and then through or in contact with W a catalyst of sufficient capacity to change all of the ozone in the air to oxygen. Heretofore attempts have been made to purify air by means of ozonizers. However, the method was to discharge ozone directly into the room to produce therein a low concentration of ozone (in the order of .01 part per million). My method differs from this in that the air is segregated in a localized zone, and there subjected to the action of a high concentration of ozone. Thereafter ozone not used in oxidizing the odoriferous compounds is removed by the action of a catalyst before discharging the segregated air back into the room.

Such an apparatus, of sufficient capacity for the load imposed upon it, has been found to free the air of tobacco smoke and odors very successfully. Tobacco smoke consists of very small particles, believed to be about 000001 inch in size. These particles are believed to consist of a nucleus of carbon or ash upon which is condensed tar, water, acids, etc. The more volatile compounds of these particles evaporate first and provide the pleasant odors of tobacco smoke, whereas the less volatile compounds are the last to evaporate and produce the stale and offensive odors so prevalent in a room after smoking has been going on for sometime. A portion of these small particles are temporarily precipitated in the ozonizer, forming a tarry coat on the surfaces of the ozonizer. This tarry coat is continually being vaporized, the vapors passing on with the air to the. reaction chamber and thence to the catalyst. The odoriferous substances are oxidized both in the ozonizer and the reaction chamber and changed into unoffensive compounds. The air from the reaction chamber then comes in contact with the catalyzer where the excess ozone is changed back to oxygen, so that when the treated air is discharged back into the room, it carries neither the offensive tobacco odors nor offensive ozone odors.

A unit which has been found to be of a capacity sufficient to clean up an ordinary ofiice room within a half hour is shown in the drawing. In the drawing, a fan 10 is driven by a suitable electric motor and is of sufilcient capacity to circulate approximately 300 cu. ft. per minute through the apparatus. The air enters the apparatus at the air inlet 9, enters the fan 10 and is forced through an ozonizer 11. The air discharged from the ozonizer 11 then passes through a reaction chamber 12 from which it discharges through a bed of catalyst 13 and is discharged back into the room at the top of the apparatus. The ozonizer is of a capacity and construction capable of precipitating tobacco smoke and at the same time producing large quantities of ozone. To this end it is made of a series of spaced glass plates 14 each having on one side attached aluminum foil layers 15 in such a manner as to provide ten air passages each measuring about 12 x 12 x 0.3 inches having glass on one side and aluminum foil on the other. These air passages are open at one end to the discharge from the fan and on the other end to the reaction chamber 12. The power for this ozonizer is furnished by a transformer rated at 450 milli-amperes and 15,000 volts. A suitable transformer is of the type now commercially used for neon signs. The ozonizer is connected to the transformer as shown in Fig. 2, each alternate aluminum foil 15 being connected to one terminal 16 of the transformer 17 and the other alternate aluminum foil 15 being connected to the remaining terminal 18 of the transformer 17.

The reaction chamber 12 may be of any suitable size to permit reaction between the ozone and particles or vapors. I have found that a chamber of approximately 1 cu. ft. is of sufficient capacity to provide the necessary reaction. The bed of catalyst 13 preferably is made by enclosing activated charcoal 19 between the brass gauze screens 20. The bed is approximately 24x24x inches in dimensions. Activated charcoal of the commercial type now on sale may be used, preferably being of the type produced from cocoanut shells and known in the trade as commercial adsorbent charcoal. Preferably it should have a capacity substantially the same as that known as gas mask activated charcoal. A suitable charcoal is 6-8 mesh inch charcoal manufactured by the Barnebey- Chaney Company of Columbus, Ohio. Suitable methods of activation for charcoal are now well known. One such method, which is satisfactory, is to subject the cocoanut shell charcoal to the action of superheated steam in accordance with the methods described by Oscar L. Barnebey. The brass gauze 20 may be of any suitable mesh sufllcient to hold the charcoal, and a mesh of 100 per square inch has been found satisfactory.

An apparatus built in accordance with the above dimensions has been found very satisfactory in maintaining an ordinary room substantially free from an offensive amount of tobacco smoke when occupied by a normal number of smokers.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. The method of purifying air laden with tobacco smoke which comprises subjecting the air to the action of ozone and thereafter to the action of a catalyst capable of restoring the ozone to oxygen.

2. The method of purifying air laden with tobacco smoke which comprises passing the air through an ozonizer and then in contact with a catalyst capable of restoring the ozone to oxygen.

3. The method of purifying air laden with tobacco smoke which comprises subjecting the air to the action of ozone and thereafter to the action of activated charcoal capable of restoring the ozone to oxygen.

4. The method of purifying air laden with tobacco smoke which comprises passing the air through an ozonizer and then in contact with activated charcoal capable of restoring the ozone to oxygen.

WILLIAM K. GILKEY. 

